During the past decade we have seen a bold new attempt to resurrect the reputation and stature of Sen. Joseph McCarthy of Wisconsin, whose Senate investigations into Communism in the 1950s led to the word “McCarthyism,” a term used ever since to describe those who smeared their opponents falsely, ruined their careers, and practiced guilt by association. The reevaluation began with a 1996 column by liberal journalist Nicholas von Hoffman, who dared to claim that while McCarthy “got it all wrong” he was still “closer to the truth than those who ridiculed him.” In 2000, Arthur Herman produced a revisionist biography of McCarthy. And, most recently, Ann Coulter wrote that McCarthy was right: Liberals back then (as now) were “systematically undermining the nation’s ability to defend itself, while waging a bellicose campaign of lies to blacken McCarthy’s name.”

Now joining the fray is longtime journalist and prominent conservative M. Stanton Evans. Rather than a biography, Evans has written a defense counsel’s brief for his client, whom he seeks to defend against all the slanders made about McCarthy by his political enemies. Like any lawyer’s argument, Evans’s brief has strengths and weaknesses. He has done extensive research, and has managed to prove that many of McCarthy’s main opponents themselves had a highly partisan agenda, bending truth in order to score points. Most important, many of his critics were so upset with McCarthy that they totally ignored or minimized the serious issue of Communist penetration of the highest levels of the government. Evans’s brief, however, is weakened by a lack of balance, and his desire to write an unabashed tribute that seeks to exonerate McCarthy on virtually every count.

Evans is on firm ground in correcting those who believe that anyone accused by McCarthy or his allies was an innocent victim pilloried for his political views. For today’s generation, which knows little about what really happened in the 1950s, Evans’s narrative will be instructive. Those who are familiar with the era, however, will find that Evans moves through well-trod ground. A slew of historians have made good use of new material from Soviet archives, as well as the decrypted Venona transcripts released by the FBI and NSA beginning in the mid-1990s. Among the scholars who have thoroughly mined these sources are Harvey Klehr, John Haynes, and Allen Weinstein in the U.S. and Christopher Andrew and Nigel West in Britain. Only a few remaining true believers — such as The Nation’s Victor Navasky — refuse to acknowledge that Soviet espionage networks were operating in the U.S., and posing a serious threat to its national security, in the 1940s.

We now know that many of those heralded as innocent victims of a McCarthyite witch hunt were in reality bona fide Soviet agents — some of them working in the White House, State Department, and OSS. Prominent among these were Alger Hiss, Duncan Lee, Maurice Halperin, Carl Marzani, Lauchlin Currie, and Harry Dexter White. (There were scores of others.) Many of them had been named first by former Communist spy Elizabeth Bentley, and McCarthy had little to do with unearthing their secret work for the Soviets.

Evans implies that only McCarthy was really on their case, while official Washington did nothing. Certainly, security procedures were lax; many liberals in and out of government sought to ignore the issue, out of fear that it would sully the reputation of the Democratic administration. Many Soviet agents actually escaped prosecution because the Venona files were not completely decrypted — and also, the decision was made not to use the ones that were, since such use would have alerted the Soviets to American intelligence successes. Not even McCarthy, who regularly got material from J. Edgar Hoover, was aware of Venona. Instead, the suspect’s names were purposefully leaked by the FBI so that the security risks would be forced out of their government jobs, once they invoked the Fifth Amendment in congressional hearings and refused to testify. To the public, invoking the Fifth branded them as potential security risks.

Evans does an impressive job of reminding readers how serious the issue of Communist penetration was. He does not emphasize, although his own data make it clear, that most of the knowledge about these people came before McCarthy was on the scene. After all, Elizabeth Bentley first went to the FBI in 1945, and named key members of Soviet networks. The FBI quickly found her information to be accurate, but was not able to use any of it in court. Nonetheless, the KGB learned that its networks had been compromised and quickly shut them down. By McCarthy’s time, they were already out of business.

While McCarthy did identify some Communists who managed to escape the net, he also began to investigate and pillory many who were in no way connected with the Soviets as agents, spies, or couriers. He often failed to distinguish between actual Communists, fellow-travelers, and anti-Communist liberals and social-democrats. It was enough for him to know that they were critical of his methods and tactics: That made them as good as Communists. Many of these people were indeed Communists, fellow-travelers, or dupes. But they were not engaged in any activity except that of public pronouncements that could be accepted or rejected on their merits. Nothing in the area of their work made them a security risk. The way Evans deals with this is highly unsatisfactory: He briefly mentions their sessions with McCarthy and ends with a short, forgettable sentence to the effect that perhaps McCarthy should not have called them. He does not even pause to ask why so many anti-Communist Americans felt nothing but hostility to McCarthy.

This is not a minor matter, because it reveals a great flaw in his book. Consider his treatment of liberal editor James Wechsler. Evans acknowledges that calling Wechsler to testify was a “dubious move,” and that McCarthy “should never have had the editor before the committee.” But Wechsler was called and questioned, and McCarthy’s treatment of him reflects why so many regarded him as a bully and a demagogue. All one has to do is read the transcripts. You will not find them quoted in Evans’s book. What you will find is that McCarthy told the fierce anti-Communist editor that he had not really broken with the Communists, and was “serving them very, very actively.” This was preposterous, since the Communist Daily Worker regularly attacked Wechsler for being anti-Communist. McCarthy thought that was all a big ruse so that Wechsler’s New York Post readers would believe him when he attacked McCarthy in his own paper.

More important to Evans’s book is the issue of Far East scholar Owen Lattimore and the Amerasia spy case of June 1945. (Full disclosure: Harvey Klehr and I are co-authors of The Amerasia Spy Case: Prelude to McCarthyism, a book from which Evans takes virtually all of his material and which he does not acknowledge.) The now-forgotten Lattimore was, after being attacked by McCarthy, elevated to the pantheon of heroes by two generations of historians and writers. He was an adviser to both Chiang Kai-shek and U.S. policymakers, and gave the advice that it was not in America’s best interests to support Chiang’s troops.

Evans easily proves that, rather than being a righteous martyr, Lattimore was a prototypical fellow-traveler of the Communists, someone who portrayed the Chinese Communists as genuine democrats. Evans easily demolishes the apologists for Lattimore by carefully dissecting what Lattimore wrote. All of that, of course, was available to anyone at the time. Evans writes: “As these quotes [from Lattimore] suggest, Lattimore seldom met a Red atrocity he didn’t like, or couldn’t find an excuse for.” Later, he writes that Lattimore’s writing proves “that he was an indefatigable shill for Moscow.” Lattimore’s real politics are hardly news, and were not at the time.

McCarthy did not stop at exposing Lattimore: He announced that Lattimore was Russia’s “top espionage agent” as well as “Alger Hiss’s boss.” Then, at a closed hearing of the Tydings Committee established to investigate McCarthy, he told the senators: “I am willing to stake my whole case on this man. If I’m wrong about him, then I am discredited as a witness.” A day later, he added that he was “willing to stand or fall on this one.” McCarthy fell, and fell hard. His over-the-top charges only created great sympathy for Lattimore, whose actual views and policy recommendations were completely ignored.

While Lattimore was a shill for the Soviets, he was hardly the spy McCarthy made him out to be. Rather than acknowledge this, Evans seeks to justify McCarthy. He does so by bending evidence to imply, without proof, that perhaps Lattimore was a spy. His biggest proof is that Lattimore’s FBI file bore the title: “Owen Lattimore, Espionage-R” (for Russia). Any historian working with FBI files knows right away that a file category means that the FBI was investigating a possibility, and offers no proof that the person so filed was any kind of agent. Evans even ignores what he quotes J. Edgar Hoover as saying, that the allegations were “unsubstantiated.”

Evans also credits ex-Communist witness Louis Budenz as further proof, since Budenz testified that he knew Lattimore to be a Communist working for the Soviets. But as Harvey Klehr and I pointed out in our book, Budenz was a most untrustworthy witness on this point. Budenz had talked to the FBI for over five years, never mentioning any connection between Lattimore and any espionage ring. Evans does show that Budenz was told this years earlier, and held the information back to use when he thought it would be most effective. But Budenz’s story was itself hearsay, and not provable. Before the Tydings Committee, moreover, Budenz falsely claimed that Lattimore was asked by the Communist party to fix the Amerasia case, and later wrote that the man asked to do that was Alger Hiss. All these charges were complete and total nonsense. Charges like these, echoed and amplified by McCarthy, were precisely what destroyed his credibility among anti-Communist Americans. Indeed, they helped actually guilty people — like Hiss — claim that they, too, were innocent victims.

Evans dredges up the Amerasia case as a key example of how espionage was swept under the carpet by the Truman administration, only to be brought up years later by McCarthy. Six people, including China hand John S. Service, had been arrested and charged with espionage on behalf of the Chinese Communists. Evans reveals that there indeed was a cover-up that got Service and the others off: one orchestrated, in Service’s case, by the great fixer Tommy “The Cork” Corcoran. All of this was disclosed in our 1996 book (and our earlier New Republic article); it is not a new revelation, although Evans tries hard to make it appear the cover-up was something he discovered. Moreover, Evans charges Service with being an actual spy, while the evidence suggests only that he was leaking material to undermine America’s pro-Chiang policy. That behavior by Service was completely reprehensible, but it was not espionage. No evidence — nothing in the FBI’s recorded wiretaps — indicates that Service was an actual agent.

In a similar fashion, Evans supports McCarthy’s outrageous assertion about Gen. George C. Marshall. It is fair game to argue that Marshall had a wrong and naïve view of Mao and his comrades — which he most certainly did. It is another to argue that he acted on behalf of the conspiracy set in motion by Service and the other China hands, who, Evans argues unconvincingly, “were controlling U.S. policy in the Pacific.” And even if Marshall was wrong, nothing can justify McCarthy’s charge that the general led a “conspiracy so immense” to undermine America.

Evans is certainly correct when he challenges McCarthy’s partisan enemies; they played rough, they were out to get him, and they often ran hearings as fraudulent and political as his own. Sen. Millard Tydings clearly did not run an honest investigation; it was a set-up to condemn McCarthy that itself dishonored the Senate. And Evans does prove that some of McCarthy’s charges were true. Most of us remember the Ed Murrow broadcasts that showed McCarthy characterizing a black woman from Washington, D.C., Annie Lee Moss, as a hidden Communist. One recalls Sen. Stuart Symington apologizing to her for the committee, making it clear that Moss did not know Karl Marx from Groucho Marx. As it turns out, McCarthy had the right woman; she was a Communist. (David Oshinsky said this in his 1983 biography of McCarthy — so this, too, is not new.) Moss never should have had a security clearance to work near the Pentagon’s code room. But even here, McCarthy never could prove, nor did he claim, that she passed anything on to the Soviets or anyone else. The Army pointed out at the time that Moss had no actual access to the code room itself or any classified material. The Moss affair was, in fact, largely irrelevant.

Finally, Evans defends the famous trips to Europe by Roy Cohn and G. David Schine to investigate U.S. Information Service libraries. It was not book-burning, he says, but a legitimate investigation to show that the libraries had far too many pro-Communist books. Evans ignores the widespread criticism of Cohn and Schine for living the high life in Europe on the taxpayer’s dime, which got as much negative publicity as anything else. He also supports McCarthy in the Army-McCarthy hearings that led to his final collapse. Evans’s most telling point is to show that the popular Army counsel Joe Welch, famous for his “Have you no sense of decency?” statement to McCarthy, was a complete phony. The name of a leftist lawyer who worked in Welch’s firm, Fred Fisher, had been spoken in the hearing room by McCarthy. Erupting in anger, Welch made his famous statement. Evans shows that, in fact, Fisher’s name had been made public by Welch himself weeks earlier in the New York Times. Welch’s public outburst was nothing more than grandstanding that allowed him to score with the TV public and to be seen, falsely, as a man of honor. But the hearing’s larger question was about the promotion of Army dentist Irving Peress to a higher rank — and Evans’s claims of the supposed dangers surrounding the dentist’s promotion do not hold up.

Evans’s book falls far short of what it might have done to correct the record about the era. His own exaggerations and unwarranted leaps parallel those made by McCarthy. It is unlikely that his hope to change history’s verdict will become a reality as a result of the publication of this book.

Mr. Radosh, an adjunct fellow at the Hudson Institute and a contributing editor of the New York Sun, has written widely on Communism and anti-Communism.